1. Field of the Invention
The present disclosure relates generally to radio frequency (RF) transmitters.
2. Background Art
Many modern communication signals include multiple orthogonal carriers (e.g., OFDM, LTE, MoCA, etc.) and thus have a Gaussian or substantially Gaussian amplitude probability density function (PDF) and high Peak to Average Power Ratio (PAPR). Traditional power amplifiers (e.g., class A) have very low power efficiency (e.g., 1-2%) when handling peak events of these signals. Common solutions for improving the power efficiency of a power amplifier include varying the power supply provided to the amplifier as a function of the amplitude of the input signal. However, these solutions are limited by the bandwidth of the input amplitude tracking circuitry and therefore are inefficient for broadband modern communication signals (e.g., LTE, modern cable TV signals, etc.).
The present disclosure will be described with reference to the accompanying drawings. Generally, the drawing in which an element first appears is typically indicated by the leftmost digit(s) in the corresponding reference number.